Coincidence imaging

Facility for coincidence imaging of coherent control

The mechanism of coherent control using femtosecond pulse shaping techniques can be studied using a novel photoelectron-photoion coincidence imaging facility operational since the spring of 2008.

A dedicated molecular beam apparatus, equiped with a state-of-the-art photoelectron-photoion coincidence imaging detector is available to measure the three-dimensional momentum distribution of correlated electrons and ions in femtosecond time-resolved experiments. The imaging detectors employ small pore (5 micron) Chevron Micro-Channel-Plate / Delay line detectors. Position and time-of-flight are measured with an 8 channel 25 ps time bin TDC. The arrival time of electrons is measured with a separate high-speed, 640 fs time bin, TAC. The electron-ion optics operate in slow-field velocity map imaging focusing conditions with time-switched lens voltages at a repetition rate of 5 kHz. The arrival time of electrons can be measured at 16 ps intrinsic time resolution and DE/E = 3.5% energy resolution near 2 eV electron energy. Ion masses can be measured with a  relative mass resolution of 1/4200.

A 5 kHz regen-amplified TiSapphire based femtosecond laser system with 2 non-collinear-opto-parametric-amplifiers (NOPA) are available to generate two independently tunable femtosecond laser pulses of 25-30 fs duration. Harmonics of both 800 nm and NOPA pulses are available.

A 640 pixels phase, amplitude and polarization pulse shaper is available for feedback or forward coherent control experiments. XFROG, SPIDER, autocorrelators and spectrum analyzers are available for pulse characterization.

This experimental facility is available for state-of-the-art femtosecond photoelectron-photoion coincidence imaging detection of coherent control experiments with full femtosecond pulse shaping control. 
foto maurice foto a maurice

Contact Person at LCVU: Maurice Janssen, email: mhmj@chem.vu.nl